package string;

import java.util.Locale;

public class TrimDemo {
    public static void main(String[] args) {
        String a="          hELLo WorLd          ";
        a=a.trim();//去空格
        System.out.println(a);
        a=a.toUpperCase();//    大写
        System.out.println(a);
        a=a.toLowerCase();//小写
        System.out.println(a);
    }
}
